This invention relates to the art of wireless communication, and more particularly, to employing space-time diversity to increase the capacity of wireless systems.
Prior art wireless communication systems, such as time division multiple access (TDMA) or code division multiple access (CDMA) wireless communications systems, are used for communicating between base stations and wireless terminals. When setting various parameters for the communication such prior art systems only consider the strength of the desired signal at the wireless terminal and fail to also take into account the interference caused by communication between the base station and others of the wireless terminals. Also, prior art wireless communication systems that employ so-called xe2x80x9cpower control,xe2x80x9d e.g., CDMA systems, perform the power control independent of any weight vectors that are used for beam forming at the base station. Additionally, power control at the base station in such prior art wireless communication systems is performed typically based only on either the pilot signal strength at the wireless terminal or the bit error rate (BER) at the wireless terminal. These design factors of prior art wireless systems cause their signal to interference and noise ratio (SINR) to be less than optimal, resulting in reduced system capacity, i.e., the system cannot serve as many active wireless terminals as it could with a higher SINR.
We have recognized that the signal to interference and noise ratio (SINR) of wireless systems can be improved, if not optimized, by determining operating parameters used by the base station to substantially simultaneously control the transmit beam patterns that are each formed to establish a communication channel between a base station and a respective one of the wireless terminals as a function of received channel information from at least two of the wireless terminals. In an exemplary embodiment of the invention, the weight vectors and the power allocation employed by a base station are determined by the base station using information supplied by at least each of the wireless terminals served by the base station, and potentially from wireless terminals served by other base stations, e.g., in neighboring cells to the cell served by the base station, the information from the other cells being supplied via the neighboring cell base stations using inter-base-station communication, e.g., a wire line connection.